Lecture 1: Introduction to the Human Brain Flashcards
What fissure separates the 2 cerebral hemispheres?
Great longitudinal fissure
What do the grooves in the brain allow?
Increase the surface area of the brain to allow greater capacity for brain function, the lower the order of species the less grooves
What is the difference between grey and white matter and where are they located?
Grey matter makes up the cerebral cortex and is on the periphery, it contains nerve cell bodies - nuclei
White matter is below the grey matter and contains axons - tracts
What are gyri and sulci?
Gyri are the folds in the brain
Sulci are the grooves
What is the name of the sulcus which separates the parietal lobe?
Central sulcus
What are the four lobes of the brain and where are the roughly located?
Frontal - front
Parietal - More posterior
Occipital - most posterior
Temporal - inferior
Which sulcus/fissure seperates the frontal and parietal lobe from the temporal lobe?
Lateral sulcus/fissure
From which surface can the central and lateral sulci be seen?
Lateral surfaces
What fissure/sulcus seperates the parietal lobe from the occipital lobe and from what surface is it visible?
Parietooccipital sulcus
In which gyrus does every motor axon originate?
Pre central gyrus
Into which gyrus do all axons that carry conscious sensation travel?
Post central gyrus
Where are the post and pre central gyrus?
Anterior (pre) and posterior (post) to the central sulcus
What are the 3 parts of the brain stem and how are they positioned?
Medulla - first dilation of the spinal cord, most inferior
Pons - in the middle
Midbrain - most superior
Where does the cerebellum lie (in relation to the brain stem)?
Posterior to the brainstem
Where does the diencephalon lie?
Superior to the brain stem
Where does the 4th ventricle lie?
Between the brain stem and the cerebellum
What 2 parts of the brain does the diencephalon contain?
Thalamus and the hypothalamus
What is the purpose of the 4th ventricle?
Helps to create and store CSF that then circulates around the brain
What is the function of the thalamus?
Important relay station between the brainstem and spinal cord and cerebral cortex
What is the function of the hypothalamus?
Controls the autonomic NS
How many pairs of cranial nerves are there?
12
Which end of the neural tube develops into the brain?
The rostral end
Which end of the neural tube develops into the spinal cord?
The caudal end
What are the 3 primary vesicles formed from the neural tube in the formation of the brain?
Prosencephalon - Most rostral
Mesencephalon
Rhombencephalon - Most caudal
What are the 5 secondary vesicles formed in the formation of the brain and from what primary vesicles do they form?
Telencephalon and Diencephalon - from the prosencephalon
Mesencephalon - from the mesencephalon
Metencephalon and Myelencephalon - from the rhombencephalon
What part of the mature brain does the telencephalon form?
the 2 cerebral hemispheres
What part of the mature brain does the mesencephalon form?
Midbrain
What part of the mature brain does the metencephalon from?
Pons and cerebellum
What part of the mature brain does the myelencephalon from?
Medulla oblongata
What 3 things does the cavity of the neural tube form in the mature CNS?
1) Ventricles - expanded cavities within the brain
2) Connecting channels - link ventricles
3) Vestigial - central canal of the spinal cord
What are the 3 meninges of the brain and how are they positioned?
1) Dura - outermost
2) Arachnoid - middle
3) Pia - innermost
What is the nature of the dura mater what is its position?
Tough fibrous membrane
Like a loose fitting bag, adhered to the inside of the skull
What is the nature of the arachnoid mater and what is its position?
Soft translucent membrane
Adhered to the underside of the dura membrane
What is the subdural space?
Potential space between the dura and arachnoid mater
What is the nature of the pia mater and what is its position?
microscopically thin, delicate membrane
Tightly adhered to the surface of the brain, following all cavities
What is the subarachnoid space and what is contained within it?
Space between the arachnoid and pia mater
Arachnoid mater sends cobweb-like projections down to the pia mater, the space contains CSF
What is the function of the meninges and the CSF?
Protect the brain, cushion and nourish
What is the falx cerebri?
A large reflection of dura mater which extends into the cranial cavity between the 2 cerebral hemispheres
What is the tentorium cerebelli?
A large reflection of dura mater which extends into the cranial cavity between the cerebrum and cerebellum
Of how many layers does the dura consist and what are they called?
2 - Outer periosteal and inner meningeal
What are dural venous sinuses and what is their function?
Spaces where the periosteal and meningeal layers of dura are not adhered together
Venous blood drains into them and then into the internal jugular vein
What is the falx cerebelli?
A reflection of dura mater which extends into the cranial cavity between the cerebellar hemispheres
What is the superior sagittal sinus?
Dural venous sinus created by the falx cerebri reflection
Where does the confluence of sinuses lie?
Posteriorly
What are the 5 major sinuses to remember and in which dural infolding are they positioned?
1) Superior sagittal sinus - Falx cerebri
2) Inferior sagittal sinus - Falx cerebri
3) Straight sinus - Falx cerebri where crossed by tentorium cerebelli
4) Right/left transverse sinus - Tentorium cerebelli
5) Sigmoid sinus - Tentorium cerebelli
What percentage of body weight is made up by the brain and what percentage of oxygen is consumed by the brain?
2% of weight
20% of oxygen consumption
What are the 2 pairs of arteries that supply the brain?
1) Vertebral arteries
2) Internal carotid arteries
Via which foramen do the verterbral arteries enter the skull?
Foramen Magnum
From which arteries do the vertebral arteries branch?
Subclavian arteries
What do the external carotid arteries supply?
Face, scalp, neck etc.
How do the internal carotids enter the skill?
Via carotid channels
What is the rough course of the vertebral arteries?
Come off subclavian and run up alongside the spinal cord within the vertebrae on the posterior surface of the neck
Which pair of arteries supplying the brain is more anterior?
The internal carotid
What are the pairs of cerebellar arteries and from where do they originate?
1) Posterior inferior cerebellar arteries from the vertebral arteries
2) Anterior inferior cerebellar arteries from the basillar artery formed from the union of the 2 vertebral arteries
3) Superior cerebellar arteries from the basillar artery just before it bifurcates
What are the pairs of cerebral arteries and from where do they originate?
1) Posterior cerebral arteries formed from the bifurcation of the basillar artery
2) Middle cerebral arteries which come off the internal carotid
3) Anterior cerebral arteries which come off the middle cerebral arteries
What is the anterior communicating artery and the posterior communicating arteries and what do they make up along with the cerebral arteries?
Anterior communicating artery - between the 2 anterior cerebral arteries
Posterior communicating arteries between the internal carotid and posterior cerebral artery
Make up the arterial surface of Willis
What are the labyrinthine arteries?
Branches off the basillar artery
Which artery supplies the vast majority of the lateral hemisphere?
Middle cerebral artery
Which artery supplies most of the pre and post central gyri?
Middle cerebral artery
Which artery projects forwards and supplies the majority of the medial surface of the brain?
Anterior cerebral arteries
Which arteries mainly supply the posterior aspect of the brain?
Posterior cerebral arteries
At the junction between what 2 parts of the brain does the basillar artery bifurcate?
Between the pons and midbrain
Which artery supplies the medial surface of the occipital lobe?
Posterior cerebral
Which arteries supply the lateral aspect of the pons?
Labyrinthine arteries
What is the anterior spinal artery a branch of?
The vertebral
